Multiple Energy Sources Toolbox Talk

Many pieces of jobsite equipment are powered by more than one energy source. A machine may have electrical power, hydraulic pressure, air pressure, stored spring tension, raised parts, batteries, fuel, heat, or gravity hazards all at the same time. Locking out only the main disconnect can leave dangerous energy behind.

This talk focuses on finding and controlling multiple energy sources before service, repair, cleaning, adjustment, or jam clearing begins. The crew needs to slow down, trace every source, control stored energy, and verify that nothing can start, move, pressurize, heat up, or release unexpectedly.

Why This Matters

• One missed energy source can defeat the whole lock out tag out process.
• Equipment can still move, drop, shock, burn, or release pressure after the main power is off.
• Different energy sources may require different locks, tags, blocks, blanks, pins, valves, or restraints.
• Multiple trades may control different parts of the same system, which increases the chance of confusion.
• Identifying all energy sources protects the worker doing the task and anyone nearby.

Common Hazards

• Electrical feeds from panels, generators, batteries, cords, temporary power, or backup systems.
• Hydraulic pressure trapped in lifts, cylinders, hoses, pumps, compactors, and attachments.
• Pneumatic pressure in air lines, compressors, tanks, tools, valves, and actuators.
• Gravity hazards from raised buckets, forks, blades, platforms, forms, gates, or suspended loads.
• Mechanical energy from belts, chains, gears, shafts, springs, flywheels, and rotating parts.
• Thermal energy from hot pipes, steam, engines, heaters, welders, process lines, and recently used equipment.
• Chemical or fuel energy from gas lines, fuel tanks, batteries, process piping, or pressurized containers.
• A machine tied into building controls, remote starters, sensors, or automatic cycles that can energize one part of the system while another part appears locked out.

Safety Checklist

Before Work Begins

• Review the equipment-specific lock out tag out procedure before starting.
• Identify every energy source connected to the equipment or system.
• Trace cords, conduits, hoses, pipes, valves, cylinders, controls, and lines back to their source.
• Check for secondary power, backup power, batteries, generators, capacitors, and automatic controls.
• Identify stored energy in raised parts, pressure lines, tanks, springs, flywheels, hot surfaces, and suspended components.
• Select the correct locks, tags, hasps, valve covers, breaker lockouts, plug lockouts, chains, blanks, pins, blocks, or cribbing.
• Notify affected workers and nearby trades before shutdown and isolation begins.
• Assign responsibility for each energy source when more than one authorized worker is involved.

During Work

• Shut down the equipment using normal controls before isolating energy sources.
• Isolate, lock, and tag each energy source at the correct control point.
• Bleed, block, discharge, lower, pin, restrain, or relieve stored energy before work starts.
• Verify zero energy for each source, not just the main electrical disconnect.
• Try the controls after lockout to confirm the equipment cannot start, move, cycle, or pressurize.
• Watch for pressure building back up, parts settling, heat remaining, or automatic controls trying to cycle.
• Stop and reassess if a new hose, wire, valve, battery, pipe, or control point is found during the task.

Crew Talking Points

• What energy sources are connected to the equipment or system today?
• Are there any secondary or backup sources that are easy to miss?
• What stored energy must be released, blocked, discharged, or restrained?
• Who is responsible for locking out each energy source?
• How will we verify that every source is controlled before work begins?
• Does anyone see another line, cord, hose, valve, control, or hazard that needs to be checked?

Stop Work If

• Any energy source has not been identified, isolated, locked, tagged, or controlled.
• The lock out tag out procedure does not match the equipment or current jobsite setup.
• Stored pressure, raised parts, spring tension, heat, or electrical energy cannot be safely controlled.
• The equipment starts, moves, cycles, sparks, leaks, heats up, or builds pressure during verification.
• There is confusion about which worker controls which lock, tag, valve, breaker, or disconnect.
• A new energy source is discovered after the work has already started.

Final Reminder

Do not stop at the main switch. Find every energy source, control each one, verify zero energy, and only then start the work.